An employee who believes she has been fired for discriminatory reasons has the right to sue her employer as soon as she receives a termination notice. That’s true even if the termination isn’t yet effective.

Sometimes, it is up to HR to stop bosses from doing the wrong thing—for example, when he is frustrated because he has to accommodate a disabled worker’s medical restrictions. If the supervisor comes up with an obviously implausible reason to fire the worker, expect trouble.

If an employee sues her employer and suddenly faces increased scrutiny, she may argue that she’s being retaliated against. She would have an even stronger case if the employer was singling her out for extra scrutiny.

Even if you think you have a rock-solid reason to fire someone, don’t count on it as an airtight defense against every lawsuit. Your rationale might, for example, be an excellent defense against an age discrimination claim, but not against an FMLA claim.

If an employee says she is going to need FMLA leave as soon as she becomes eligible, terminating her may amount to interference with the right to take FMLA leave. That’s true even though she wasn’t eligible for leave when she was fired.

Do you think you may have slightly underpaid an employee who is being terminated? Paying her a little extra as she heads out the door may fix that problem without penalty, based on California wage payment rules.

What not to do when closing down offices in which workers are older than the company average: Mention that eventually you may be able to hire younger replacements at lower cost. That’s just asking for a lawsuit.